Comparative Analysis of Polimeric Insulators Under Pollution and External Defect Using the Finite Element Method

摘要

This work presents an evaluation of electric field and electric potential in polymeric insulators under different operating conditions. The conditions considered were: intact insulator, with the presence of an external defect and under effect of pollution. Thus, two 138 kV polymeric insulators from different manufacturers were modeled with the aid of multiphysics simulation software that uses Finite Element Method. A thin conductive layer was modeled on the surface of the insulators, in order to investigate the influence of pollution on their electrical performance. The external defect was represented by a cavity deep enough to reach the interface between the coating and the core. In the simulations carried out on polluted insulators, it was detected that the insulator has a resistive characteristic, with low intensity electric field peaks. While the analysis of defective insulators showed that electric field suffers distortions, the intensity of this distortions was sufficient to cause air ionization, localized disruptive discharge and progressive degradation of the polymeric material. From the results obtained for each insulator, it was possible to observe electrical characteristics of the two topologies of polymeric insulators in view of application of different operating conditions